'It's the biggest black hole that's been weighed in this early period of the Universe,' Onken said. Not only do we not know how it formed and grew, we don't know how black holes can grow that massive so soon after the Big Bang. We don't know how supermassive or ultramassive black holes form and grow.Д«ut J2157*, hanging around when the Universe was less than 10 percent of its current age, is in a class of its own. The black holes of Holm 15A and TON 618 are pretty difficult to understand. And then there's the ultramassive black hole powering the quasar TON 618 - an absolute beast at 66 billion solar masses. An ultramassive black hole clocking in at around 40 billion solar masses is at the heart of the galaxy Holm 15A, around 700 million light-years away. J2157* is not the heftiest black hole ever discovered. But even such relatively small details matter when it comes to understanding what our Universe was up to when it was barely 1 billion years old. The adjustment is minuscule given its overall distance from us - just a few tens of millions of light-years. Those new measurements have revised not just the size and accretion rate of the black hole, but the distance. Therefore, J2157*'s event horizon is over five times the size of the Solar System. The heliopause - where the solar wind is no longer strong enough to push against interstellar space - is thought to be over 100 AUВ from the Sun. At its newly derived mass, the J2157 black hole (J2157*) would have a Schwarzschild radius - the radius of its event horizon - of around 670 astronomical unitsВ (AU).ДЇor context, Pluto is, on average, 39.5 astronomical units from the Sun. Since then, astronomers have taken new measurements to revise these numbers. The discovery of the behemoth in question was first announced in 2018 it powers a blazing quasar in the centre of a galaxy called SMSS J215728.21-360215.1 (J2157 for short) in the early Universe, billions of light-years away.ДЄt time of discovery, astronomers estimated the black hole's mass at around 20 billion solar masses, putting it in the category of ultramassive (over 10 billion solar masses), and its accretion rate - how much material it devours - at half a solar mass a day. 'If the Milky Way's black hole wanted to grow that fat, it would have to swallow two thirds of all the stars in our galaxy.' 'The black hole's mass is also about 8,000 times bigger than the black hole in the centre of the Milky Way,' said astronomer Christopher Onken of Australian National University in Australia.

This makes it the fastest-growing black hole we know of in the entire Universe its enormity tips it into the category of ultramassive black holes.

Ton 618 black hole